Aberration correction system and astronomical telescope having the same

Abstract

An aberration correction system having a first lens disposed at an object side; and a second lens disposed at an image side, wherein the first and second lenses have different dispersions (Abbe numbers) with respect to each other, the surface of the object side of the first lens and the surface of the image side of the second lens which is adjacent to the image have substantially common center of curvature and the first and second lenses rotate around the center of curvature.

What is claimed is: 
     
       1. An atmospheric dispersion correction lens system comprising, in order from a light entrance side to a light exit side, a first lens and a second lens, wherein the difference in the Abbe numbers of said first and second lenses is at least 20 and the refractive indexes of said first and second lenses differ by 0.01 or less,   wherein said first lens has a spherical surface on the light entrance side and said second lens has a spherical surface on the light exit side, and the spherical surfaces have a substantially common center of curvature, and   wherein said first and second lenses are rotatable as a unit around the common center of curvature to adjust a tilt angle of an optical axis of said first and second lenses with respect to an optical axis of said aberration correction system so as to correct a deviation of an image occurring due to the atmospheric dispersion.   
     
     
       2. An atmospheric dispersion correction lens system according to claim 1, wherein said first and second lenses are cemented together. 
     
     
       3. An atmospheric dispersion correction lens system according to claim 1, wherein said first and second lenses are separated by an air gap. 
     
     
       4. An atmospheric dispersion correction lens system according to claim 1, wherein said first lens has a refractive index of 1.567322 and an Abbe number of 42.83, and said second lens has a refractive index of 1.569069 and an Abbe number of 71.30. 
     
     
       5. An atmospheric dispersion correction lens system according to claim 1, wherein the spherical surface of said first lens is concave to the light entrance side and the spherical surface of said second lens is convex to the light exit side. 
     
     
       6. An atmospheric dispersion correction lens system comprising, in order from a light entrance side to a light exit side, a first lens and a second lens, wherein the difference in the Abbe numbers of said first and second lenses is at least 20 and the refractive indexes of said first and second lenses differ by 0.01 or less,   wherein the surface of the light entrance side of said first lens and the surface of the light exit side of said second lens are plane surfaces which are perpendicular to the optical axis of said atmospheric dispersion correction lens system, and   wherein said first and second lenses are translatable as a unit in a direction perpendicular to the optical axis of said atmospheric dispersion correction lens system to adjust an amount of decentering of said first and second lenses with respect to the optical axis of said atmospheric dispersion correction lens system so as to correct a deviation of an image occurring due to atmospheric dispersion.   
     
     
       7. An atmospheric dispersion correction lens system according to claim 6, wherein said first and second lenses are cemented together. 
     
     
       8. An atmospheric dispersion correction lens system according to claim 6, wherein said first and second lenses are separated by an air gap. 
     
     
       9. An astronomical telescope comprising: a concave reflecting mirror; and   an atmospheric dispersion correction lens system, comprising, in order from a light entrance side to a light exit side, a first lens and a second lens, wherein the light entrance side is the side from which the light is reflected by said concave reflecting mirror and the light exit side is the other side,   wherein the difference in the Abbe numbers of said first and second lenses is at least 20 and the refractive indexes of said first and second lenses differ by 0.01 or less,   wherein said first lens has a spherical surface on the light entrance side and said second lens has a spherical surface on the light exit side, and the spherical surfaces have a substantially common center of curvature, and   wherein said first and second lenses are rotatable as a unit around the common center of curvature to adjust a tilt angle of an optical axis of said first and second lenses with respect to an optical axis of said aberration correction system so as to correct a deviation of an image occurring due to the atmospheric dispersion.   
     
     
       10. An astronomical telescope according to claim 9, wherein said first and second lenses are cemented together, wherein the spherical surface of said first lens is concave to the light entrance side and the spherical surface of said second lens is convex to the light exit side, and   wherein said astronomical telescope comprises in adjacent order from the light entrance side to the light exit, after said concave reflecting mirror: (a) a meniscus positive lens having a convex surface facing the object side;   (b) a meniscus negative lens and having a convex surface facing the light entrance side;   (c) said atmospheric dispersion correction lens system; and   (d) a biconvex positive lens.     
     
     
       11. An astronomical telescope according to claim 10, wherein said lenses (a), (b), and (d) are fixed and are made of borosilicate crown glass. 
     
     
       12. An astronomical telescope according to claim 11, wherein said lens (b) has an aspherical concave surface on the light exit side and said lens (d) has an aspherical surface on the light entrance side. 
     
     
       13. An astronomical telescope according to claim 12, wherein said first lens has a refractive index of 1.567322 and an Abbe number of 42.6, and said second lens has a refractive index of 1.569069 and an Abbe number of 71.30. 
     
     
       14. An astronomical telescope comprising: a concave reflecting mirror; and   an atmospheric dispersion correction lens system, comprising, in order from a light entrance side to a light exit side, a first lens and a second lens, wherein the light entrance side is the side from which the light is reflected by said concave reflecting mirror and the light exit side is the other side,   wherein the difference in the Abbe numbers of said first and second lenses is at least 20 and the refractive indexes of said first and second lenses differ by 0.01 or less,   wherein the surface of the light entrance side of said first lens and the surface of the light exit side of said second lens are plane surfaces which are perpendicular to the optical axis of said atmospheric dispersion correction lens system, and   wherein said first and second lenses are translatable as a unit in a direction perpendicular to the optical axis of said atmospheric dispersion correction lens system to adjust an amount of decentering of said first and second lenses with respect to the optical axis of said atmospheric dispersion correction lens system so as to correct a deviation of an image occurring due to atmospheric dispersion.   
     
     
       15. An astronomical telescope according to claim 14, wherein said first and second lenses are cemented together. 
     
     
       16. An astronomical telescope according to claim 14, wherein said first and second lenses are separated by an air gap. 
     
     
       17. An astronomical telescope comprising: a concave reflecting mirror; and   an aberration correction optical system for correcting aberrations generated by said concave reflecting mirror, said optical system including an atmospheric dispersion correction lens system comprising, in order from a light entrance side to a light exit side, a first lens and a second lens, wherein the light entrance side is the side from which the light is reflected by said concave reflecting mirror and the light exit side is the other side,   wherein the difference in the Abbe numbers of said first and second lenses is at least 20 and the refractive indexes of said first and second lenses differ by 0.01 or less,   wherein said first lens has a spherical surface on the light entrance side and said second lens has a spherical surface on the light exit side, and the spherical surfaces have a substantially common center of curvature, and   wherein said first and second lenses are rotatable as a unit around the common center of curvature to adjust a tilt angle of an optical axis of said first and second lenses with respect to an optical axis of said aberration correction system so as to correct a deviation of an image occurring due to the atmospheric dispersion.   
     
     
       18. An astronomical telescope according to claim 17, wherein said first and second lenses are cemented together, wherein the spherical surface of said first lens is concave to the light entrance side and the spherical surface of said second lens is convex to the light exit side, and   wherein said astronomical telescope comprises in adjacent order from the light entrance side to the light exit, after said concave reflecting mirror: (a) a meniscus positive lens having a convex surface facing the object side;   (b) a meniscus negative lens and having a convex surface facing the light entrance side;   (c) said atmospheric dispersion correction lens system; and   (d) a biconvex positive lens.     
     
     
       19. An astronomical telescope according to claim 18, wherein said lenses (a), (b), and (d) are fixed and are made of borosilicate crown glass. 
     
     
       20. An astronomical telescope according to claim 19, wherein said lens (b) has an aspherical concave surface on the light exit side and said lens (d) has an aspherical surface on the light entrance side. 
     
     
       21. An astronomical telescope according to claim 20, wherein said first lens has a refractive index of 1.567322 and an Abbe number of 42.6, and said second lens has a refractive index of 1.569069 and an Abbe number of 71.30. 
     
     
       22. An astronomical telescope according to claim 17, wherein said atmospheric dispersion correction lens system consists of said first lens and said second lens. 
     
     
       23. An astronomical telescope comprising: a concave reflecting mirror; and   an aberration correction optical system for correcting aberrations generated by said concave reflecting mirror, said optical system including an atmospheric dispersion correction lens system comprising, in order from a light entrance side to a light exit side, a first lens and a second lens, wherein the light entrance side is the side from which the light is reflected by said concave reflecting mirror and the light exit side is the other side,   wherein the difference in the Abbe numbers of said first and second lenses is at least 20 and the refractive indexes of said first and second lenses differ by 0.01 or less,   wherein the surface of the light entrance side of said first lens and the surface of the light exit side of said second lens are plane surfaces which are perpendicular to the optical axis of said atmospheric dispersion correction lens system, and   wherein said first and second lenses are translatable as a unit in a direction perpendicular to the optical axis of said atmospheric dispersion correction lens system to adjust an amount of decentering of said first and second lenses with respect to the optical axis of said atmospheric dispersion correction lens system so as to correct a deviation of an image occurring due to atmospheric dispersion.   
     
     
       24. An astronomical telescope according to claim 23, wherein said first and second lenses are cemented together. 
     
     
       25. An astronomical telescope according to claim 23, wherein said first and second lenses are separated by an air gap. 
     
     
       26. An astronomical telescope according to claim 23, wherein said atmospheric dispersion correction lens system consists of said first lens and said second lens.